An investigation into lens cell membrane component synthesis, specifically cholesterol, and its relation to the process of cataractogenesis. The control of endogenous cholesterol synthesis from isotopically-labeled precursors by exogeneous aqueous humor lipiprotein cholesterol will be investigated. The lipids of the lipoproteins and lens cell membranes from both animals and humans will be analyzed, including normal and cataractous subjects. The effect of desmosterol on lens cell cholesterol synthesis will be investigated.